CN114586260A

CN114586260A - Rotor of rotating electric machine

Info

Publication number: CN114586260A
Application number: CN202080070842.8A
Authority: CN
Inventors: 中滨敬文; 清水伸一; 村上理; 渡边纮和; 小山泰平; 伊藤晓
Original assignee: Toshiba Corp; Toshiba Infrastructure Systems and Solutions Corp
Current assignee: Toshiba Corp; Toshiba Infrastructure Systems and Solutions Corp
Priority date: 2019-10-08
Filing date: 2020-10-06
Publication date: 2022-06-03
Anticipated expiration: 2040-10-06
Also published as: WO2021070823A1; CN114586260B; JP6848029B1; JP2021061701A; TW202121798A; TWI778425B; EP4044412A4; EP4044412A1

Abstract

The present invention relates to a rotor of a rotating electric machine. According to an embodiment, a rotor of a rotating electrical machine includes: a rotating shaft (30); a rotor core (32) coaxially fixed to the rotating shaft; a plurality of rotor bars (60) which are inserted into slots (50) of the rotor core and have a 1 st bar end (40a) extending from a 1 st end surface (32a) of the rotor core in the axial direction and a 2 nd bar end extending from a 2 nd end surface of the rotor core in the axial direction; an annular 1 st end ring (42a) fixed to the projecting end of the 1 st end; and an annular 2 nd end ring fixed to the projecting end of the 2 nd bar end. The rotor bars each have a swaging groove (61) extending in the axial direction and facing the opening portion, and a 1 st end swaging groove (61a) formed continuously with the swaging groove at a 1 st bar end, the 1 st end swaging groove extending obliquely from the 1 st end surface (32a) position toward the 1 st end toward the radial outer side of the rotor core.

Description

Rotor of rotating electric machine

Technical Field

Embodiments of the present invention relate to a rotor of a rotating electric machine having rotor bars.

Background

As an example of a rotating electrical machine, an induction motor having a cage-type rotor structure is known. The cage rotor includes a rotor core, a plurality of rotor bars embedded in the rotor core, and end rings connecting the rotor bars outside the rotor core. The rotor bar is inserted into a slot arranged on the rotor core. Both axial end portions (bar ends) of the rotor bar protrude outward from both end surfaces of the rotor core, respectively. The rotor bar is fixed to the insertion slot of the rotor core by performing swaging processing, such as forming a swaged slot, on the rotor bar. Generally, the swaged groove is formed in the range of the rotor core, not in the bar end.

The plurality of strip ends are arranged in a circumferential state from the end face of the rotor core to the end ring, and the strip ends function as a radial fan as the rotor rotates. That is, as the rotor rotates, wind flows in a radial direction, and wind flowing at a speed close to the peripheral speed of the rotor is generated on the outer peripheral side of the bar end. When the motor is operated, a current flows through the rotor bars, and the rotor bars generate heat due to joule loss, but the rotor bars and the rotor are cooled by the flow of the wind. In recent years, with the progress of brazing technology, the bar end length has become gradually smaller. This reduces the heat dissipation area of the bar end, thereby reducing the cooling performance. As a result, the temperature rise of the rotor increases.

Documents of the prior art

Patent literature

Patent document 1: japanese laid-open patent publication No. 11-18344

Disclosure of Invention

Problems to be solved by the invention

An object of an embodiment of the present invention is to provide a rotor of a rotating electric machine capable of improving cooling performance.

Means for solving the problems

According to an embodiment, a rotor of a rotating electrical machine includes: a rotating shaft which is freely rotatable around a central axis; a rotor core coaxially fixed to the rotating shaft, the rotor core including: a 1 st end surface located at one axial end side and a 2 nd end surface located at the other axial end side; an outer peripheral surface coaxial with the central axis; a plurality of slots formed to penetrate in the axial direction, each of the slots being open at the 1 st end surface and the 2 nd end surface and being provided at intervals in the circumferential direction of the outer peripheral surface; and a plurality of openings formed in the outer peripheral surface, extending in the axial direction, and communicating with the insertion grooves; a plurality of rotor bars inserted into the slots, respectively, and having a 1 st bar end axially extending from the 1 st end surface and a 2 nd bar end axially extending from the 2 nd end surface; an annular 1 st end ring fixed to a projecting end of the 1 st end; and an annular 2 nd end ring fixed to the projecting end of the 2 nd end. Each of the rotor bars has a swage groove extending in the axial direction and facing the opening portion, and a 1 st end swage groove formed continuously with the swage groove at a 1 st end of the rotor bar, and the 1 st end swage groove extends obliquely from a position of the 1 st end face toward a radial outer side of the rotor core toward the 1 st end ring.

Drawings

Fig. 1 is a longitudinal sectional view showing a part of a rotating electric machine according to an embodiment.

Fig. 2 is an enlarged cross-sectional view of a part of the rotor of the rotating electric machine taken along line a-a of fig. 1.

Fig. 3 is a side view showing one end portion of the rotor in the axial direction partially cut.

Fig. 4 is a sectional view of the outer peripheral portion of the rotor taken along line B-B of fig. 3.

Fig. 5 is a sectional view schematically showing one bar end of the rotor bar.

FIG. 6A is a cross-sectional view of the rotor bar end along line C-C of FIG. 3.

Fig. 6B is an enlarged sectional view showing the swaged groove portion of the rotor bar end.

FIG. 7A is a cross-sectional view of the rotor bar end along line D-D of FIG. 3.

Fig. 7B is an enlarged sectional view showing the swaged groove portion of the rotor bar end.

Fig. 8 is a view schematically showing the rotor bar and the swaged groove.

Fig. 9 is an enlarged cross-sectional view of a bar end portion of a rotor according to modification 1.

Fig. 10 is a cross-sectional view showing a rotor bar portion of a rotor according to modification 2.

Fig. 11 is a cross-sectional view showing a rotor bar portion of a rotor according to modification 3.

Fig. 12 is a cross-sectional view showing a rotor bar portion of a rotor according to modification 4.

Fig. 13 is a cross-sectional view showing a rotor bar portion of a rotor according to modification 5.

Detailed Description

Hereinafter, various embodiments will be described with reference to the drawings. Note that, the same reference numerals are given to the components common to the entire embodiments, and redundant description is omitted. The drawings are schematic views for facilitating understanding of the embodiments, and the shapes, dimensions, proportions, and the like of the drawings differ from those of actual apparatuses, and these can be appropriately designed and changed with reference to the following description and known techniques.

(embodiment mode)

Fig. 1 is a longitudinal sectional view showing a half-divided portion along a central axis of a rotary electric machine according to an embodiment.

As shown in fig. 1, the rotating electrical machine 10 is configured as an inner rotor type rotating electrical machine, for example. The rotating electric machine 10 includes a casing 12 sealed inside, a stator (stator)14 disposed in the casing 12, and a cage-type rotor (rotor) 16.

The housing 12 includes a substantially cylindrical frame 18, a 1 st disc-shaped bracket 19 attached to and closing one axial end of the frame 18, and a 2 nd disc-shaped bracket 20 attached to and closing the other axial end of the frame 18. A 1 st bearing case 22a having a bearing B1 built therein is bolted to a center portion of the 1 st bracket 19. A 2 nd bearing case 22B having a bearing B2 built therein is bolted to a center portion of the 2 nd bracket 20. The bearings B1 and B2 are arranged along the central axis C1 of the rotating electric machine 10.

The stator 14 includes a cylindrical stator core 24 and a stator coil 28 wound around the stator core 24. The stator core 24 is supported by the frame 18 with its outer peripheral surface engaged with the inner peripheral surface of the frame 18, and is disposed coaxially with the central axis C1. A pair of

annular core holders

26a and 26b are fixed to both end surfaces in the axial direction of the stator core 24. The stator core 24 is formed by laminating a plurality of annular metal plates made of a magnetic material, for example, a silicon steel plate. A plurality of slots each extending in the axial direction are formed in the inner peripheral portion of the stator core 24. The stator coil 28 is mounted to the stator core 24 in a state of being embedded in these slots. The coil ends 28e of the stator coil 28 axially project from both end faces of the stator core 24.

The rotor 16 includes a rotating shaft 30, a rotor core (rotor core) 32, a plurality of rotor bars 40 embedded in the rotor core 32, and a pair of

end rings

42a and 42b connected to both ends of the rotor bars 40. The rotary shaft 30 is disposed in the housing 12 coaxially with the center axis C1, and one end portion and the other end portion in the axial direction are rotatably supported by bearings B1 and B2, respectively. The driving side end 30a of the rotating shaft 30 protrudes outward. A joint for connecting a driving gear unit and the like is attached to the driving side end portion 30 a.

The rotor core 32 is formed by laminating a plurality of annular metal plates made of a magnetic material, for example, a silicon steel plate, and is formed into a substantially cylindrical shape. The rotor core 32 is attached to a substantially central portion of the rotary shaft 30 in the axial direction, and is disposed inside the stator core 24 coaxially with the center axis C1. The outer peripheral surface of the rotor core 32 faces the inner peripheral surface of the stator core 24 with a gap G. The axial length of the rotor core 32 is formed substantially equal to the axial length of the stator core 24. The rotor core 32 has a 1 st end surface 32a located at one end in the axial direction and a 2 nd end surface 32b located at the other end in the axial direction. The 1 st end surface 32a and the 2 nd end surface 32b extend substantially orthogonally to the center axis C1.

The rotor core 32 is supported so as to be sandwiched from both axial end sides by a pair of

core holders

34a and 34b attached to the rotary shaft 30. The core

pressing plates

34a and 34b are formed in a ring shape, and the outer diameter thereof is formed smaller than the outer diameter of the rotor core 32.

Fig. 2 is a sectional view of the rotor taken along line a-a of fig. 1, and fig. 4 is an enlarged sectional view of a rotor bar portion of the rotor.

As shown in fig. 1 and 2, a plurality of ventilation ducts 44 are formed through the rotor core 32 and the

core holders

34a and 34b in the axial direction. The plurality of ventilation ducts 44 are provided at intervals in the circumferential direction around the center axis C1.

A plurality of slots (grooves) 50 extending in the axial direction are formed in the outer peripheral portion of the rotor core 32, and the plurality of slots 50 are arranged at regular intervals in the circumferential direction. Each slot 50 extends through the rotor core 32 in the axial direction and opens at the 1 st end face 32a and the 2 nd end face 32 b. Each slot 50 is open to the outer periphery of the rotor core 32 via an opening 52 having a circumferential width W2. The opening 52 extends over the entire axial length of the rotor core 32. The cross-sectional shape of the insertion groove 50 is rectangular, for example. The circumferential width W1 of the slot 50 is set to be larger than the circumferential width W2 of the opening 52.

The rotor bar 40 is inserted through each slot 50 and extends in the axial direction of the rotor core 32. The cross-sectional shape of the rotor bar 40 is, for example, a rectangular shape having a size (dimension) corresponding to the cross-sectional shape of the slot 50. As shown in fig. 2 and 4, the rotor bar 40 has a pair of short side surfaces (an upper surface 41a and a lower surface 41b) facing each other and a pair of long side surfaces (a pair of side surfaces 41c) facing each other. The rotor bar 40 is disposed in the slot 50 with the upper surface 41a facing the outer peripheral surface of the rotor core 32, that is, with the upper surface 41a facing the opening 52.

As shown in fig. 1, one end portion (1 st end) 40a in the longitudinal direction of the rotor bar 40 extends outward from the 1 st end face 32a of the rotor core 32. The other end portion (2 nd end) 40b in the longitudinal direction of the rotor bar 40 extends outward from the 2 nd end surface 32b of the rotor core 32. The projecting length of the 1 st end 40a and the projecting length of the 2 nd end 40b are set to be substantially equal.

As an example of the swaging process, the rotor bar 40 is caulked and fixed to the insertion groove 50 of the rotor core 32 by forming the swaging groove 60 in the upper surface 41a of the rotor bar 40. That is, the pair of side surfaces 41c of the rotor bar 40 is pressed against the rotor core 32 and fixed to the rotor core 32.

An annular end ring 42a is fixed to the projecting end of the 1 st bar end 40 a. The end ring 42a is disposed coaxially with the center axis C1, and connects the plurality of bar ends 40a to each other. An annular end ring 42b is fixed to the projecting end of the 2 nd bar end 40 b. The end ring 42b is disposed coaxially with the center axis C1, and connects the plurality of bar ends 40b to each other. The rotor bars 40 and the end rings 42a and 42b are made of a conductive metal material such as aluminum or copper.

The plurality of rotor bars 40 and the pair of

end rings

42a, 42b constitute a cage rotor of the induction motor. When the stator coil 28 is energized, the rotor core 32 is induced to rotate, and the rotary shaft 11 and the rotor core 32 rotate integrally.

Next, the forging groove 60 will be described in detail.

Fig. 3 is a side view showing one end portion of the rotor in the axial direction partially cut, fig. 4 is a sectional view of the outer peripheral portion of the rotor taken along line B-B of fig. 3, and fig. 5 is a sectional view schematically showing one end of the rotor bar.

As shown in fig. 3 and 4, the swage groove 60 is formed using, for example, a disk-shaped pressing roller R having an outer peripheral edge sharpened in a triangular shape. The outer peripheral portion of the pressing roller R is pressed against the upper surface 41a of the rotor bar 40 through the opening 52 of the rotor core 32, and the pressing roller R is moved along the opening 52 while rotating, thereby forming the swaged groove 60 in the upper surface 41a of the rotor bar 40. At this time, the pressing roller R is moved in the axial direction from the substantially center of the rotor bar 40 in the longitudinal direction toward the 1 st bar end 40a, and then, the pressing roller R is moved in the axial direction from the substantially center of the rotor bar 40 in the longitudinal direction toward the 2 nd bar end 40 b. Thus, the rotor bar 40 has the swaged groove 60 formed therein to a predetermined depth over the entire length of the region located in the insertion groove 50 of the rotor core 32. The swaged groove 60 has a triangular cross-sectional shape with the apex of the triangle forming the bottom edge 61 of the groove.

As shown in fig. 3, in the machining of the swage groove 60, the pressing roller R is moved toward the 1 st end 40a to a position where the rotation center C2 of the pressing roller R coincides with the 1 st end face 32a of the rotor core 32. Thereby, the 1 st end swage groove 60a continuous with the swage groove 60 is formed at the 1 st end 40 a. As shown in fig. 3 and 5, the 1 st end swaging groove 60a projects from the 1 st end face 32a toward the projecting end of the 1 st rod end 40a by a length L1. The 1 st end swaging groove 60a is formed to have a depth gradually shallower from the 1 st end surface 32a to the 1 st groove end S2. That is, the bottom edge 61a of the 1 st end swaging groove 60a extends obliquely toward the radially outer side of the rotor core 32 from the bottom edge 61 (base end S1) of the swaging groove 60 to the 1 st groove end S2 on the upper surface 41a at the position of the 1 st end face 32 a. In the present embodiment, the bottom edge 61a extends while being curved in an arc shape.

Fig. 6A is a sectional view of a rotor bar end taken along line C-C of fig. 3, fig. 6B is a sectional view showing an enlarged view of a swaged groove portion of the rotor bar end shown in fig. 6A, fig. 7A is a sectional view of the rotor bar end taken along line D-D of fig. 3, and fig. 7B is a sectional view showing an enlarged view of the swaged groove portion of the rotor bar end shown in fig. 7A.

As shown in fig. 5, 6A, and 6B, in the 1 st end swaged groove 60a provided in the 1 st bar end 40a, the groove depth is formed deep at a position (base end portion) close to the rotor core 32 substantially equal to the depth of the swaged groove 60. By the rotation of the rotor 16, an air flow CF flowing on the outer peripheral side of the 1 st streak end 40a is generated. By this air flow CF, a vortex SW1 having a high flow rate and a large size is generated in the 1 st end swaging groove 60 a.

On the other hand, as shown in fig. 7A and 7B, in the 1 st end swaged groove 60a, the depth of the groove is formed to be shallower than the depth of the groove at the base end at a position (tip end) distant from the rotor core 32. Therefore, by the air flow CF, a vortex SW2 having a low flow rate and a small flow rate is generated in the 1 st end swaging groove 60a of the front end portion.

As shown in fig. 5, in the 1 st end swaging groove 60a, the flow velocity and the static pressure of the vortex generated on the base end side and the tip end side are different from each other. That is, the flow velocity of the vortex is high and the static pressure PS1 is small at the base end side of the 1 st end swaging groove 60a, whereas the flow velocity of the vortex is low and the static pressure PS2 is large at the tip end portion of the 1 st end swaging groove 60a (PS2> PS 1). As a result, the axial flow AF is generated in the 1 st end swage groove 60a from the tip end portion side where the flow velocity is low and the static pressure PS2 is large to the base end portion side where the flow velocity is high and the static pressure PS1 is small. By this axial flow AF, the air in the 1 st end swaging groove 60a flows into the 1 st end swaging groove 60a from the outer peripheral side of the 1 st groove end (tip) S2 of the 1 st end swaging groove 60a, and flows out from the rising start point (base end) S1 side of the 1 st end swaging groove 60a toward the outer peripheral side of the 1 st bar end 40 a. The air circulating into the 1 st end swaging groove 60a receives heat from the 1 st end 40a and increases in temperature, but does not reach a high temperature. By providing the swaging grooves 60 and the 1 st end swaging groove 60a in this manner, the heat radiation area of the rotor bar 40 is increased, and the temperature of the air in the 1 st end swaging groove 60a does not increase, so that the heat radiation of the 1 st bar end 40a can be promoted. Therefore, the cooling performance of the rotor bars 40 and the rotor core 32 is improved, and the temperature of the rotor can be reduced.

Further, as described above, when the pressing roller R for swaging groove processing is rotated and pressed from the center side of the rotor core 32 toward the 1 st end surface 32a, the rotor bar 40 is warped toward the outer peripheral side, but by rotating and pressing the pressing roller R to a position where the rotation center C2 of the pressing roller R coincides with the 1 st end surface 32a of the rotor core 32, warping of the rotor bar 40 can be suppressed. There is no need for subsequent processing such as suppression of the occurrence of warpage and cutting of the tip end portion of the rotor bar.

Fig. 8 is a view schematically showing a rotor bar and a swaged groove.

The swage groove may be provided only at one 1 st bar end 40a, but may be provided at both bar ends. As shown in fig. 8, according to the present embodiment, the 2 nd end swaging groove 60b continuous with the swaging groove 60 at the center is formed at the 2 nd bar end 40 b. In a state where the pressing roller R is pressed against the upper surface 41a of the rotor bar 40, the pressing roller R is moved from the center portion of the rotor core 32 in the axial direction toward the 2 nd bar end 40b in the axial direction while continuously rotating in the axial direction, whereby the swaged groove 60 is formed in the upper surface 41a of the rotor bar 40. In the machining of the swage groove 60, the pressing roller R is moved toward the 2 nd bar end 40b until the rotation center C2 of the pressing roller R is positioned slightly before the 2 nd end face 32b of the rotor core 32. Thereby, the 2 nd end swaging groove 60b continuous with the swaging groove 60 is formed in the 2 nd bar end 40 b.

The 2 nd end swaging groove 60b projects from the position of the 2 nd end face 32b toward the projecting end of the 2 nd bar end 40b by a length L2. The axial length L2 is different from the axial length L1 of the 1 st end swage groove 60a on the other end side. That is, the length L2 is set shorter than the length L1 (L2< L1). The 2 nd end swaging groove 60b is formed to have a depth gradually reduced from the position of the 2 nd end surface 32b to the 2 nd groove end. That is, the bottom edge 61b of the 2 nd end swaging groove 60b extends obliquely toward the radial outside of the rotor core 32 from the bottom edge 61 of the swaging groove 60 to the 2 nd slot end on the upper surface 41a at the position of the 2 nd end surface 32 b. In the present embodiment, the bottom edge 61b extends while being curved in an arc shape.

As shown by the arrow in fig. 8, when the rotor 16 rotates, in the 1 st end swaging groove 60a, as described above, the air flows in from the outer peripheral side of the rising tip (1 st groove end) S2 of the 1 st end swaging groove 60a into the 1 st end swaging groove 60a and flows out from the rising start point (base end) S1 side of the 1 st end swaging groove 60a toward the outer peripheral side of the 1 st bar end 40a by the axial flow AF.

In the 2 nd end swaging groove 60b, air flows into the 2 nd end swaging groove 60b from the outer peripheral side of the rising tip (2 nd groove end) of the 2 nd end swaging groove 60b by the axial flow, and flows out from the rising start point (base end) side of the 2 nd end swaging groove 60b toward the outer peripheral side of the 2 nd strip end 40 b.

Further, in the 1 st end swage groove 60a having the long axial length L1, the swage groove in the vicinity of the 1 st end face 32a of the rotor core 32 is deep, and a large vortex flow having a high flow velocity is generated by the air flowing on the outer peripheral side of the 1 st bar end 40 a. On the other hand, in the 2 nd end swage groove 60b having the short axial length L2, the swage groove in the vicinity of the 2 nd end face 32b of the rotor core 32 is shallow, and a vortex flow having a low flow rate and a small flow velocity is generated in the 2 nd end swage groove 60 b. Further, an axial flow is generated in the swaging grooves 60 formed in the center portion of the rotor bar 40, flowing from the 2 nd end swaging groove 60b side, where the flow velocity is low and the static pressure is large, toward the 1 st end swaging groove 60a side, where the flow velocity is high and the static pressure is low, on the opposite side. Air in the gap, the rotor core 32, and the opening 52 flows toward the 1 st bar end 40a through the swaging groove 60, and low-temperature air flows into the swaging groove 60 from the 2 nd end swaging groove 60b side. Therefore, the air gap, the rotor core 32, the rotor core near the opening 52, and the rotor bars 40 radiate heat to the air at a lower temperature, and therefore, the heat radiation of the rotor 16 is promoted, and the temperature of the rotor 16 can be reduced.

According to the rotor 16 of the rotating electrical machine 10 of the present embodiment configured as described above, cooling of the rotor bars 40 and the rotor core 32 can be promoted by devising the swaged grooves 60 of the rotor bars 40, and cooling performance can be improved. This improves cooling performance and can provide a rotor of a rotating electric machine with a reduced temperature.

Next, a rotor of a rotating electric machine according to a modification of the present invention will be described. In the modification described below, the same portions as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof is omitted or simplified, and the portions different from the embodiment will be mainly described in detail.

(modification 1)

Fig. 9 is an enlarged cross-sectional view of a bar end portion of the rotor according to modification 1.

The bottom edge 61a of the 1 st end swaging groove 60a is not limited to being inclined on a circular arc, and may be inclined and extended linearly from the base end S1 to the tip end S2 as shown in the drawing.

The same operational effects as those of the above embodiment can be obtained also in the 1 st end swaging groove 60a as described above.

(modification 2)

Fig. 10 is an enlarged cross-sectional view of a rotor bar portion of a rotor according to modification 2.

As shown in the drawing, according to the 2 nd modification, the cross-sectional shape of the rotor bar 40 is formed in a polygonal shape, for example, a trapezoidal shape, in which the length (circumferential width) of the upper surface (1 st side) 41a facing the opening 52 is larger than the length (circumferential width) of the lower surface (surface on the rotation axis side) (2 nd side) 41b on the opposite side. The pair of side surfaces 41c are inclined in such a manner as to become tapered toward the lower surface 41 b. The slots 50 of the rotor core 32 are formed in a sectional shape corresponding to the size and shape of the rotor bars 40. The width W1 of the upper surface 41a is greater than the width W2 of the opening 52.

When the peripheral edge portion of the pressing roller R for swaging the groove is pressed against the upper surface 41a of the rotor bar 40 through the opening 52, the rotor bar 40 is fixed to the rotor core 32 in a state where the pair of side surfaces 41c are pressed against the inclined surfaces 51c of the slot 50 and the shoulder portions 43b on the upper surface 41a side of the rotor bar 40 are plastically deformed and pressed against the shoulder portions 51b of the slot 50. From one end to the other end of the rotor core 32 in the axial direction, the side surfaces 41c of the rotor bars 40 abut against the inclined surfaces 51c of the slots 50, and the shoulders 43b of the rotor bars 40 abut against the shoulders 51b of the slots 50, so that the thermal contact resistance between the rotor bars 40 and the rotor core 32 is reduced. This facilitates heat generation of the rotor bars 40 to be transmitted to the rotor core 32 and the rotating shaft having a large heat capacity, thereby promoting heat dissipation of the rotor bars 40 and reducing the temperatures of the rotor bars 40 and the rotor core 32. In modification 2, the same operational effects as those of the above embodiment can be obtained.

(modification 3)

Fig. 11 is an enlarged cross-sectional view of a rotor bar portion of a rotor according to modification 3.

As shown in the drawing, according to the modification 3, the opening 52 of the rotor core 32 is formed so as to gradually increase in width from the outer peripheral surface of the rotor core 32 toward the upper end of the slot 50, i.e., the upper surface 41a of the rotor bar 40. The width of the end of the opening 52 on the slot 50 side is substantially the same as the width W1 of the upper surface 41 a. By widening the width of the opening 52 in this manner, the cross-sectional area of the opening 52 is increased.

In a rotor of an axial ventilation type or a rotating electric machine having a structure in which a rotor core is skewed, when a pressure difference exists between both sides of the rotor core 32 in the axial direction, air in the machine is ventilated from the opening 52 in the axial direction. At this time, by setting the cross-sectional area of the opening 52 to be large as described above, the ventilation resistance becomes small and the flow rate increases. This promotes heat dissipation from rotor core 32 and rotor bars 40, thereby achieving a reduction in the temperature of the rotor.

(modification 4)

Fig. 12 is an enlarged cross-sectional view of a rotor bar portion of a rotor according to modification 4.

As shown in the drawing, according to the 3 rd modification, the opening 52 of the rotor core 32 is formed so as to gradually increase in width from the outer peripheral surface of the rotor core 32 toward the upper end of the slot 50, that is, the upper surface 41a of the rotor bar 40. The width of the end portion of the opening 52 on the slot 50 side is set smaller than the width W1 of the upper surface 41 a. By widening the width of the opening 52 in this manner, the cross-sectional area of the opening 52 is increased.

Since the width W1 of the upper surface 41a of the rotor bar 40 is larger than the width of the lower end of the opening 52, when the peripheral edge portion of the pressing roller R is pressed against the upper surface 41a of the rotor bar 40, the rotor bar 40 is fixed to the rotor core 32 in a state in which the pair of side surfaces 41c are pressed against the inclined surfaces 51c of the slot 50 and the shoulders 43b of the upper surface 41a of the rotor bar 40 are plastically deformed and pressed against the shoulders 51b of the slot 50. From one end to the other end of the rotor core 32 in the axial direction, the side surfaces 41c of the rotor bars 40 abut against the inclined surfaces 51c of the slots 50, and the shoulders 43b of the rotor bars 40 abut against the shoulders 51b of the slots 50, so that the thermal contact resistance between the rotor bars 40 and the rotor core 32 is reduced. Further, by increasing the width of the opening 52, the ventilation resistance of the axial flow decreases, and the ventilation flow rate increases. This promotes heat dissipation from the rotor bars 40 and the rotor core 32, thereby improving the cooling performance of the rotor.

(modification 5)

Fig. 13 is an enlarged cross-sectional view of a rotor bar portion of a rotor according to modification 5.

As shown in the figure, the cross-sectional shape of the rotor bar 40 is not limited to a trapezoid, and may be formed in other polygonal shapes, for example, a pentagonal cross-section. Rotor bar 40 has upper surface 41a facing opening 52 and lower surface 41b on the opposite side, and die forging groove 60 is provided in upper surface 41 a. The width W1 of the rotor bar 40 is largest at the approximate middle between the upper surface 41a and the lower surface 41 b. The respective curved and inclined side surfaces 41c are pressed against the corresponding inclined surfaces of the insertion groove 50. The slot-side end of the opening 52 has a circumferential width gradually increasing to substantially match the width of the upper surface of the rotor bar 40.

In the 5 th modification having the above configuration, the same operational effects as in the 3 rd modification and the 4 th modification can be obtained.

Although several embodiments and modifications of the present invention have been described, these embodiments and modifications are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in other various ways, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the scope equivalent thereto.

Claims

1. A rotor of a rotating electric machine is provided with:

a rotating shaft which is freely rotatable around a central axis;

a rotor core coaxially fixed to the rotating shaft, the rotor core including: a 1 st end surface located at one axial end side and a 2 nd end surface located at the other axial end side; an outer peripheral surface coaxial with the central axis; a plurality of slots formed to penetrate in the axial direction, each of the slots being open at the 1 st end surface and the 2 nd end surface and being provided at intervals in the circumferential direction of the outer peripheral surface; and a plurality of openings formed in the outer peripheral surface, extending in the axial direction, and communicating with the insertion grooves;

a plurality of rotor bars inserted into the slots, respectively, and having a 1 st bar end axially extending from the 1 st end surface and a 2 nd bar end axially extending from the 2 nd end surface;

an annular 1 st end ring fixed to a projecting end of the 1 st end; and

an annular 2 nd end ring fixed to the projecting end of the 2 nd end,

each of the rotor bars has a swage groove extending in the axial direction and facing the opening portion, and a 1 st end swage groove formed continuously with the swage groove at a 1 st end of the rotor bar, and the 1 st end swage groove extends obliquely from a position of the 1 st end face toward a radial outer side of the rotor core toward the 1 st end ring.

2. The rotor of a rotary electric machine according to claim 1,

the rotor bars each have a 2 nd end swaging groove formed continuously with the swaging groove at the 2 nd bar end, and the 2 nd end swaging groove extends obliquely outward in the radial direction of the rotor core from the 2 nd end face position toward the 2 nd end ring.

3. The rotor of a rotary electric machine according to claim 2,

when the length of the 1 st end swaging groove in the axial direction from the 1 st end surface to the groove end is set to the 1 st length and the length of the 2 nd end swaging groove in the axial direction from the 2 nd end surface to the groove end is set to the 2 nd length, the 1 st length and the 2 nd length are different from each other.

4. The rotor of the rotating electric machine according to any one of claims 1 to 3,

the rotor bar has a polygonal cross-sectional shape in which the length of the 1 st side facing the opening is longer than the length of the 2 nd side facing the 1 st side.

5. The rotor of the rotating electric machine according to any one of claims 1 to 3,

the opening portion has a width along the circumferential direction, and the width along the circumferential direction is increased from the outer peripheral surface side toward the slot side.

6. The rotor of the rotating electric machine according to any one of claims 1 to 3,

the rotor bar has a 1 st surface having a 1 st width along the circumferential direction and facing the opening, and a width of an end of the opening on the slot side along the circumferential direction is smaller than the 1 st width.

7. The rotor of the rotating electric machine according to any one of claims 1 to 3,

the 1 st end swaging groove extends from the 1 st end face to a projecting end of the groove in a bent manner.

8. The rotor of the rotating electric machine according to any one of claims 1 to 3,

the 1 st end swaging groove extends linearly and obliquely from the 1 st end face to a projecting end of the groove.